Method of making a wheel end assembly with a machined rotor having reduced on-vehicle runout

ABSTRACT

A method of making a wheel end to be installed on a vehicle includes assembling a rotor and components with bearing surfaces to define an assembled module configured to be mounted to the vehicle, and preloading the bearing surfaces of the assembled module in a set amount as required for mounting the assembled module to the vehicle. The method further includes mounting the assembled module on a holding fixture and rotating the assembled module on the holding fixture. The method further includes, while rotating the preloaded assembled module, machining the face of the hub flange prior to affixing a rotor to the flange, and then machining a final cut on the rotor once the rotor is affixed to the flange. After machining, the assembled module remains preloaded with the set amount of preload as the assembled module is installed on the vehicle, thereby providing reduced lateral runout.

BACKGROUND OF THE INVENTION

The present invention is related to wheel ends and a method of making awheel end to be installed on a vehicle for reduced runout of thevehicle.

Wheel ends and brake modules for motor vehicles are known and have beenwidely used in the automotive industry for many years. A typical wheelend of a vehicle generally includes a hub to which a half shaft or stubshaft attaches for rotation about an axis. A bearing assembly isdisposed on the hub and mounts within a body of a steering knuckle toallow the half shaft, for example, to rotate and drive the hub about theaxis. A rotor may be attached to the hub for rotational movement aboutthe axis.

BRIEF SUMMARY OF THE INVENTION

Thus, it is one aspect of the present invention to provide an improvedmethod of making a wheel end to be installed on a vehicle for reducedlateral runout.

It is another aspect of the present invention to provide a method ofmaking a wheel end wherein machining a final cut on a rotor of the wheelend is performed after assembling and preloading the module forinstallation on a vehicle.

Another aspect of the present invention includes a method of making awheel end wherein a preload is maintained while machining a final cut ona rotor of the wheel end and up to installation thereof on a vehicle.

It is yet another aspect of the present invention to provide a wheel endor brake module having a hub and a rotor attached thereto. The hubincludes a flange and a hub shaft having inboard and outboard ends. Theflange extends from the hub shaft at the outboard end. The rotor ismounted to the flange for radial movement with the hub. The rotor ismachined after assembling and preloading the wheel end.

In one embodiment, a method of the present invention includes assemblingthe rotor and components with bearing surfaces to define an assembledmodule which is configured to be installed on the vehicle. The methodfurther includes preloading the bearing surfaces, after the rotor andcomponents are assembled, to define a preloaded condition of theassembled module. When assembled and preloaded, the assembled wheel endremains assembled and preloaded for installment on a vehicle. The methodfurther includes mounting the assembled wheel end on a holding fixtureand rotating the assembled wheel end about an axis on the holdingfixture.

Furthermore, the method includes machining a final cut on the rotor to arotor width while rotating, after assembling and preloading theassembled module to define the wheel end to be installed on the vehicle.Then, the wheel end remains assembled and preloaded for installment on avehicle. It has been determined that machining the final cut on therotor after assembling and preloading the module provides asubstantially reduced on-vehicle or lateral runout on the vehicle solong as the wheel end remains assembled and preloaded for installation.This provides a reduced lateral runout on the vehicle.

It has been determined that the wheel end provides substantial reductionto lateral runout, since after machining the wheel end remains assembledand preloaded up to installation of the wheel end on the vehicle. Thisprevents and avoids additional interfaces and, in turn, additionalrunout to the wheel end after machining the final cut on the rotor.

Further objects, features and advantages of the invention will becomeapparent from consideration of the following description and theappended claims when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wheel end having reduced lateralrunout in accordance with one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the wheel end taken along lines 22in FIG. 1;

FIG. 3 is an end view of the wheel end depicting a flange of a hub towhich a rotor may be mounted;

FIG. 4 is an exploded view of the wheel end of FIG. 1 in accordance withone embodiment of the present invention;

FIG. 5 is an end view of the wheel end depicting a rotor in accordancewith one embodiment of the present invention; and

FIG. 6 is a flow chart depicting one method of making the wheel end forreduced runout on a vehicle for reduced runout in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 illustrate a wheel end 10 for a vehicle having reducedlateral runout in accordance with the present invention. As shown, thewheel end 10 generally includes a hub 13 and a hub pilot 13 b to which arotor 14 is mounted or affixed via bolts 47. As best seen in FIG. 2, abearing assembly 49 is disposed about the hub 13 and is received withina steering knuckle 17 which is mounted to the vehicle. As shown, a wheelend shaft or a mating shaft or a constant velocity joint housing andshaft housing and shaft 18 are disposed through the hub 13 and rotor 14to allow the wheel end 10 to be driven.

FIG. 2 depicts a cross-sectional view of the wheel end 10 of FIG. 1. Asshown, wheel end 10 comprises hub 13 including a flange 16 and a hubshaft 20 having inboard and outboard ends 22 and 23. The flange 16extends from the hub shaft 20 at the outboard end 23. The hub shaft 20includes a stepped boss 24 formed radially thereon for receiving racesas described below. The hub shaft 20 defines a splined receiving bore 26formed therethrough. The receiving bore 26 is configured to receive amating shaft or constant velocity joint housing and shaft housing andshaft 18 to define an axis A about which the hub 13 may rotate.

As shown in FIGS. 2-4, the flange 16 includes a face 28 having aplurality of mounting bores 30 formed therethrough for mounting therotor 14 on the face 28 of flange 16. The face 28 additionally has atleast one setting bore 31 formed therethrough and having internalthreads. As illustrated in FIG. 3, the face 28 of flange 16 includesinner portion 32 and outer portion 34 which may be machined to a flangewidth or thickness as mentioned below. Face 28 further includes anannular groove 36 formed radially thereon and in alignment with mountingbores 30. The thickness between the inner and outer portions 32, 34 ofthe flange is greater than the thickness of the flange at the annulargroove 36.

The annular groove 36 allows compensation of potential volcanoing when abolt 47 is inserted through mounting bore 30. Volcanoing as known, isunderstood to be excess material and flash within walls defining themounting bores displaced therethrough during assembly of the wheel end.The annular groove 36 provides a space or void in which the excessmaterial may be received, preventing additional runout and otherundesirable results. As shown in FIG. 3, the annular groove 36 isradially formed about the face 28 of flange 16 and is in alignment witheach of the mounting bores 30.

FIGS. 2 and 5 depict a rotor 14 including inboard hub mounting surface42 and outboard wheel mounting surface 43 and having a setting aperture45 and a plurality of apertures 46 formed therethrough. When apertures45 and 46 and bores 30 and 31 are in alignment, bolts 47 may be disposedthrough bore 30 and aperture 46 and set screw 48 may be disposed throughbore 31 and aperture 45 to mount rotor 14 onto flange 16.

Wheel end 10 further includes bearing assembly 49 radially disposedabout hub shaft 20 on its outer surface 24. Bearing assembly 49 isabutted by a stepped boss 29 at the outboard end 23 and by the constantvelocity joint housing and shaft 18 at the inboard end 22. Bearingassembly 49 includes inboard inner bearing race 50 and outboard innerbearing race 51 having inboard inner raceway 52 and outboard innerraceway 53, respectively, formed thereon. Bearing assembly 49 furtherincludes outer bearing race 56 having inboard outer raceway 57 andoutboard outer raceway 58. The bearing assembly 49 is configured suchthat inboard and outboard inner bearing races 50, 51 cooperate withouter bearing race 56. Thus, inboard and outboard inner bearing races50, 51 cooperate with outer bearing race 56 such that inboard innerraceway 52 is in alignment with inboard outer raceway 57 to housebearings 60 therein. Moreover, outboard inner raceway 53 is in alignmentwith outboard outer raceway 58 to house bearing 60 therein. As shown,inboard and outboard inner bearing races 50, 51 are radially disposedabout hub shaft 20 on stepped boss 24.

FIGS. 2 and 4 further illustrate a steering knuckle 17 having a body 73and first and second knuckle arms 74, 75 extending from the body 73. Thefirst and second knuckle arms 74, 75 are mounted to a strut or an uppercontrol arm and a low control arm, respectively, of the motor vehicle(not shown). As shown, steering knuckle 17 receives bearing assembly 49mounted therein. The body 73 includes an inner wall 76 formedtherethrough to define a center bore 80 of the body.

As shown, the bearing assembly 49 is disposed in center bore 80 andengages with inner wall 76 to be mounted therein. Constant velocityjoint housing and shaft housing and shaft 18 is disposed through thereceiving bore 26 of hub shaft 20 and through the center bore 80 ofsteering knuckle 17. In this embodiment, constant velocity joint housingand shaft housing and shaft 18 is a half shaft having a bell 90 and astem 92 extending therefrom. Stem 92 has an outer surface having anexternal spline to be received in the receiving bore 26. The splinedreceiving bore 26 of hub shaft 20 is configured to cooperate with theexternal spline of stem 92. This allows torque to be transferred, asknown, to provide rotation of rotor 14 about axis A. The stem's externalspline is in mating relationship with internal spline of the hub'sreceiving bore 26, as known in the art.

The constant velocity joint housing and shaft housing and shaft 18 issecured therein by locking nut 86 which locks onto a threaded portion atthe end of the constant velocity joint housing and shaft housing andshaft. This allows the rotor and hub to be driven or rotated about axisA by the constant velocity joint housing and shaft 18. In operation, theconstant velocity joint housing and shaft 18 is powered by the vehicleto rotate or drive the rotor to which a wheel (not shown) may bemounted. Although the constant velocity joint housing and shaft 18 isshown as a half shaft for a driven wheel end, a stub shaft fornon-driven wheel may be used without falling beyond the scope or spiritof the present invention.

It is understood that the wheel end depicted in FIGS. 1-5 and discussedabove is merely one example of a wheel end which may be machined inaccordance with the present invention. Other designs and configurationsof a wheel end may be used and do not fall beyond the scope or spirit ofthe present invention. For example, the hub shaft may be configured tohave one or a plurality of raceways integrally formed thereon therebyeliminating the need for one or a plurality of inner bearing races orbearing surfaces.

FIG. 6 illustrates a flow chart of one method 110 of making a wheel endor brake module mentioned above to be installed on a vehicle for reducedlateral runout. Method 110 includes assembling a rotor and componentswith bearing surfaces to define an assembled wheel end or brake moduleconfigured to be mounted to the vehicle in box 113. The components withbearing surfaces may include the knuckle, hub, bearing assembly, andconstant velocity joint housing and shaft discussed above. As mentionedabove, the rotor and corresponding components with bearing surfaces areassembled to define the wheel end as shown in FIG. 1.

In box 116, the method 110 further includes preloading the assembledwheel end. This may be accomplished by tightening the constant velocityjoint housing and shaft 18 with the nut 86, and applying force onto thebearing assembly to create a preload on the bearing assembly. In thisembodiment, the step of preloading includes applying a set amount ofradial load and thrust load on the components with bearing surfaces formounting the assembled module to the vehicle.

It is to be understood that the step of preloading the assembled wheelend includes applying a thrust load and/or a radial load to the bearingassembly as typically known. This may be accomplished by applying anaxial load on the wheel end shaft with the locking nut. However, othermeans of preloading may be used and do not fall beyond the scope orspirit of the present invention. In this embodiment, the step ofpreloading includes applying a set amount of radial load and thrustload, e.g. about 40,000 to 180,000 Newtons, on the components withbearing surfaces for mounting the assembled module to the vehicle.

Then, in box 120, the method further includes mounting the assembledwheel end on a holding fixture. In this embodiment, the holding fixturemay be a multi-jaw chuck, e.g., a three-jaw chuck. However, the holdingfixture may be any other fixture to which the assembled wheel is to bemounted, e.g., other multi-jaw chucks, a vehicle, or a suspensionsub-frame module of a vehicle. In this embodiment, the constant velocityjoint housing and shaft (mentioned above) may be a half shaft for adriven wheel end. However, a stub shaft for a non-driven wheel end maybe implemented without falling beyond the scope or spirit of the presentinvention. The steering knuckle is mounted onto the holding fixture sothat the components with bearing surfaces and the rotor are rotatableabout axis A.

Method 110 further includes rotating the assembled module about axis Aon the holding fixture in box 123. This allows the rotor to be driven orrotated about axis A in preparation for machining a final rotor cut. Themethod may further include measuring the actual runout of the assembledmodule when rotating about axis A.

Preferably, but not necessarily, the method 110 may include machining afinal hub cut on the face of the flange. The machining apparatus may beconfigured to cut the inner and/or outer portions of the flange at apredetermined flange width. In this embodiment, the apparatus only cutsthe inner and outer portions without contacting the surface of theannular groove. It is to be noted that the flange width may be anydesired width so long as the flange width is not less than the width ofthe walls defining the annular groove. It has been determined that thefinal hub cut provides a reduced runout on the vehicle so long as thepreload is maintained up to installation of the wheel end on thevehicle.

Method 110 further includes machining a final rotor cut on the rotor toa rotor width in box 126, while rotating, after assembling andpreloading the assembled module. To accomplish this, any suitablemachining apparatus or device may be used to machine the final rotor cuton the rotor to the rotor width. In this embodiment, machining the rotoris based on the measured or actual runout of the assembled module toreduce the measured runout therefrom. It has been determined thatmachining the rotor reduces runout to about 10 to 50 micron. In thisembodiment, the rotor width may be about 10-100 millimeters. The finalrotor cut represents a last cut performed on the rotor prior toinstallation of the wheel end to the vehicle. In this embodiment, therotor width may be reduced by 200-1,200 microns.

It has been determined that machining the final rotor cut on the rotorafter assembling the module and preloading the module provides a wheelend having a substantially reduced runout on the vehicle. It has beenfurther determined that the result is a substantial reduced runoutrelative to other wheel ends. After machining the final cut on therotor, the wheel end is maintained in its assembled and preloadedcondition in box 130. Thus, the wheel end is to be installed on thevehicle without any disassembling or further unloading or preloading. Asa result, a runout of about 10-50 micron after machining the final cuton the rotor remains constant when the wheel end is installed on thevehicle. This avoids added runout to the wheel end and additionalmachining caused by further disassembling and unloading after the finalcut.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

What is claimed is:
 1. A method of making a wheel end to be installed ona vehicle featuring reduced lateral runout, wherein the wheel end asinstalled on the vehicle requires a set amount of radial and thrustbearing preload, the method comprising: assembling a hub and componentswith bearing surfaces to define an assembled module configured to bemounted to the vehicle, wherein the hub includes a hub flange definingan outboard face for axially supporting a rotor, and the components withbearing surfaces cooperate to define bearings supporting the hub forrelative rotation within the assembled module; preloading the bearingsof the assembled module to the set amount to thereby define a preloadedcondition of the assembled module; mounting the assembled module on aholding fixture rotatable about a reference axis; while rotating theassembled module on the holding fixture about the reference axis,machining the face of the hub flange; securing a rotor to the hub flangeface while maintaining the assembled module on the holding fixture;while rotating the assembled module and secured rotor about thereference axis, machining a cut on the rotor to a rotor width to definethe wheel end; and removing the wheel end from the holding fixture whilemaintaining the assembled module in the preloaded condition.
 2. Themethod of claim 1 wherein rotating the assembled module includes drivingthe assembled module on the holding fixture about an axis for machiningthe rotor.
 3. A method of making a wheel end to be installed on avehicle for reduced lateral runout, wherein the wheel end as installedon the vehicle requires a set amount of radial and thrust bearingpreload, the method comprising: assembling a rotor, a hub including ahub flange to which the rotor is axially secured, and components withbearing surfaces to define an assembled module configured to be mountedto the vehicle; preloading the components with bearing surfaces of theassembled module to be mounted to the vehicle by applying the set amountof radial load and thrust load on the bearing surfaces to define apreloaded condition of the assembled module; mounting the assembledmodule within a knuckle; fixturing the knuckle so as to permit relativerotation of the hub; machining the hub flange while rotating the the hubabout a reference axis; securing the rotor to the machined hub flangewhile maintaining the knuckle fixtured; and, machining a final cut onthe rotor while rotating the the hub about the reference axis; to definethe wheel end; and maintaining the assembled module in the preloadedcondition before installing the wheel end on the vehicle.
 4. The methodof claim 3 further comprising measuring runout of the vehicle based onthe assembled module before machining the rotor.
 5. The method of claim4 wherein machining the rotor is based on the measured runout of theassembled module to reduce the measured runout.
 6. The method of claim 3wherein rotating the assembled module includes driving the assembledmodule on a holding fixture about the reference axis.
 7. A method ofmaking a wheel end to be installed on a vehicle for reduced lateralrunout, wherein the wheel end as installed on a vehicle requires a setamount of radial and thrust bearing preload, the method comprising:assembling a hub and components with bearing surfaces to define anassembled module configured to be mounted to the vehicle, wherein thehub includes a hub flange defining an outboard face, and the componentswith bearing surfaces cooperate to define bearings supporting the hubfor relative rotation within the assembled module; preloading thebearings of the assembled module by applying the set amount of bearingpreload to thereby define a preloaded condition of the assembled module;mounting the assembled module on a holding fixture; machining theoutboard face of the hub while rotating the hub of the mounted assembledmodule about a reference axis; affixing the rotor to the face of the hubwithout removing the assembled module from the holding fixture; andmachining a final rotor cut on the rotor while rotating the hub of themounted assembled module about the reference axis.
 8. The method ofclaim 7 including dismounting the assembled module from the holdingfixture while maintaining the assembled module in the preloadedcondition before installing the wheel end on the vehicle.
 9. The methodof claim 8 further comprising measuring runout of the assembled modulein the preloaded condition before machining the rotor.
 10. The method ofclaim 9 wherein machining the rotor is based on the measured runout ofthe assembled module to reduce the measured runout therefrom.
 11. Themethod of claim 8 wherein the final cut on the rotor represents a lastcut performed on the rotor prior to installation of the wheel end on thevehicle.